Automatic mechanism for phonograph record playing apparatus



Jan. 26, 1954 RAE 2,667,250

AUTOMATIC MECHANISM FOR PHONOGRAPH RECORD PLAYING APPARATUS Filed March6, 1951 2 Sheets-Sheet l ,/37 FIG.

' l6 s 4 I820 I? 2 3 I2 ,17 w 7 6 13 11,2 l4\ I;ill]llllllllllllllllllllllll" .ALEXANDER JAMES RAE 5y dam W FF Jan. 26,1954 A. J. RAE 2,667,250 AUTOMATIC MECHANISM FOR PHONOGRAPH RECORDPLAYING APPARATUS Filed March 6, 1951 2 Sheets-Sheet 2 fizz/e072,ALEXANDER dAMES RAE Patented Jan. 26, 1954 AUTOMATIC MECHANISM FORPHONO- GRAPH RECORD PLAYING APPARATUS Alexander James Rae, West Ealing,London, England, assignor to Electric & Musical Industries Limited,Hayes, England, a company of Great Britain Application March 6, 1951,Serial No. 214,051

Claims priority, application Great Britain March 8, 1950 5 Claims.

This invention relates to automatic control mechanism for phonographrecord playing apparatus.

In some forms of automatic control mechanism the automatic cycle iseifected under the control of a control disc which after the playing ofa record is automatically coupled to the drivmg motor of the phonographvia a driving member which engages with the periphery of said disc, thelatter having a peripheral recess which, after the completion of theautomatic cycle is disposed adjacent said driving member so that thecontrol disc is disengaged from said driving member and comes to rest.In order to initiate the automatic cycle it is necessary to impart animpulse to the disc so as to move it angularly and thereby bring thenon-recessed part of the control disc into engagement with said drivingmember. Such angular movement is generally imparted to the disc underthe action of the transducer arm as the needle moves in the run-out oreccentric groove of the record, and therefore originates from thelateral pressure between said groove and the needle, and accordingly,there is a tendency for the needle to jump out of the groove and fail toinitiate the automatic cycle, and also damage may be caused to therecord. This tendency is increased in the case of long playing recordshaving minute record grooves.

The object of the invention is to provide improved control mechanismcomprising a control disc which does not require an impulse to beimparted from the transducer arm to the control disc for the initiationof the automatic cycle.

According to the invention there is provided automatic mechanism for aphonograph record playing apparatus comprising a control disc whichrequires it to be driven to effect the automatic cycle, a clutchcomprising a driven element coupled with said disc and a driving elementcoupled with said motor, means for causing said driving element toengage said driven element when an automatic cycle is to be effected anda cam operated by said disc for moving said driving element out ofengagement with said driven element when the automatic cycle has beeneffected, wherein in order to prevent said cam from obstructing asubsequent movement of said driving element into engagement with saiddriven element means are provided whereby after the disengagement ofsaid driving element from said driven element said control disc isfurther driven until said cam has moved from its obstructing position.

In order that the said invention may be clearly understood and readilycarried into eifect, an embodiment thereof will now be described by wayof example with reference to the accompanying drawings, in which- Figure1 is a part-sectional elevation of part of a phonograph embodying theinvention,

Figure 2 is a plan view of the control disc and a driving gear Wheel,and

Figure 3 is a plan view showing the connec tion between the pick-up anda trip lever.

Referring to the drawings the phonograph shown comprises a turntable Imounted on a shaft 2 which projects through a bracket 3, bearings 4being provided between the turntable I and the bracket 3. A drivenelement formed by a gear wheel 5 loosely mounted on the shaft 2 isarranged to be in continuous engagement with the toothed periphery of acontrol disc 6 rotatably mounted on a shaft I secured by bolts 8 and 9to a projecting arm I0 of the bracket 3. The turntable I is arranged tobe driven by an electric motor (not shown) which for example drives apulley engaging the rim of the turntable. A driving element is formed bya further gear wheel II mounted on the shaft 2 above the gear wheel 5,the gear wheel II being movable longitudinally, that is to sayvertically, on the shaft 2 but being non-rotatable with respect to theshaft 2 by virtue of a grub screw I2 which is secured into the gearwheel II and projects into a vertical key-way I3 in the shaft 2. Theopposed faces of said gear wheels 5 and II are formed with teeth I4 andrecesses I5 respectively so that the gear wheels form a dog clutch. Inorder to lift the upper gear wheel II at appropriate times a plunger I6is provided which is movable vertically in the arm ll! of bracket 3 saidplunger I6 being provided with a plate I! which projects beneath aflange I8 on the upper end of the upper gear wheel I I, so that when theplunger I6 is raised the plate I! lifts the upper gear wheel II out ofengagement with the lower gear wheel 5. In the raised position of theplunger a trip lever l9 projects under a shoulder 20 on the plunger I6as shown in Figure l and prevents the plunger I5 from dropping until thetrip lever I9 is moved from beneath shoulder 20 at the end of theplaying of a record as will be hereinafter described. With the plungerI6 in its raised position, therefore, there is no driving connectionbetween the phonograph driving motor and the control disc 6, since theturntable I is not coupled to the disc 6 via the above-mentioned dogclutch. However, when the trip lever I9 is moved from beneath shoulder20 after the playing of a record the plunger l6 drops until its lowerend engages the bottom of an annular groove 2! in the upper surface ofthe control disc 5, the lowering of the plate I! enabling the upper gearwheel H to drop into engagement with the lower gear wheel under theaction of gravity. A driving connection is thereby established betweenthe phonograph driving motor and the control disc 6, and the latteraccordingly rotates so as to effect the various operations of theautomatic cycle such as the lifting of the transducer arm from therecord, the feeding of a further record to the turntable and thelowering of the transducer arm so that the needle engages the peripheryor first groove of the further record. When the control disc 8 hasrotated sufficiently far for the automatic cycle to be completed, a camformed by a ramp 22 in the groove 2! causes the plunger it to rise untilthe trip lever I!) again engages beneath the shoulder on the plunger itunder the action of a spring 39 (Figure 3). As the plunger it rises theplate I! thereon lifts the upper gear wheel II, by engaging with theflange E8 on the upper gear wheel i I so that the dog clutch becomesdisengaged.

If the control disc 6 were to come to rest at this time, with the ramp22 still beneath the plunger IS, the latter would not be able to dropagain upon a further operation of the lever If! after the playing of afurther record, and a further automatic cycle could not be initiated. Itis therefore necessary for the control disc fi to be rotated through afurther angle sufiicient for the ramp 22 to move from under the plungerIt.

For this purpose the control disc G is provided over a suitableperipheral portion with teeth 23 of greater height than those on theremaining portion of the periphery, said teeth 23 engaging with theupper gear wheel I! as the ramp 22 commences to lift the plunger 16, andremaining in engagement therewith after the upper gear wheel it has beenmoved to its raised position so as to maintain a driving connection fora further period between the driving motor and the control disc 6. Thecontrol disc 6 accordingly continues to be rotated, after the dog clutchhas been disengaged as above-described, until the ramp 22 moves fromunder the plunger, at which time also the peripheral portion of thecontrol disc provided with the teeth 23 moves away from the upper gearwheel I! so that the control disc is no longer driven and comes to rest.

The manner in which the trip lever i9 is operated at appropriate timesunder the control of the pick-up arm is shown in Figure 3. The pick-uparm 24 is mounted on an angularly movable shaft 25 on which is mountedan arm 23 connected by a link 2'! to a bar 28 pivotally connected to anarm 29 which is angularly movable about a vertical pivot 30. The triplever i9 is formed as a bell crank lever and is pivotally mounted at 32,the said spring 39 urging one arm of the trip lever towards the plungerIS. The other arm of said trip lever projects into the path of a pin 32.on bar 28 so that when the pick-up moves inwardly to an appropriateextent after the playing of a record the pin 32 engages the trip leverand moves it away from plunger 16. When the pick-up is swung outwardlyby the automatic mechanism the trip lever I9 is again moved towards theplunger l6 by the spring 39.

It will be seen that the energy required for initiating the automaticcycle is solely that required to cau e h og utch to e a a d iconsiderably less than in mechanism in which 4 the control disc requiresto be moved angularly to establish a driving connection with the motor.In the particular arrangements above described it is merely necessary tooperate the trip lever !9 to cause the dog clutch to engage, thedownward movement of the upper gear wheel l i being thereupon effectedunder the action of gravity.

The control disc 6 carries a pin 33 which is connected by a link 34 toan arm 35 projecting from an angularly movable member so that as thecontrol disc it rotates the member 36 is moved angularly and asdescribed in British Patent No. 617,864 a sleeve 31 is moved angularlyto remove a recq d from an offset portion 38 of the record post.

What I claim is:

1. Automatic mechanism for phonograph rec ord playing apparatuscomprising a control disc, means for driving said disc, a clutchincluding a driven element coupled to said disc, a driving elementcoupled to said driving means, means for engaging said driving elementwith said driven element to drive said disc to initiate an automaticcycle, means operated from said disc to move said driving element out ofengagement vith said driven element after a predetermined angularmovement of said control disc, and means for coupling said drivingelement with the disc to drive the disc for a limited extent beyond saidpredetermined angular movement.

2. Automatic mechanism for phonograph record playing apparatuscomprising a control disc, means for driving said control disc throughone revolution to elfect an automatic cycle, a clutch comprising adriving element coupled to said driving means and a driven elementcoupled to said control disc, control means for engaging said clutchelements to couple said control disc to said driving means, and meansoperated from said control disc for disengaging said clutch elementswhen said control disc has moved through a substantial part of onerevolution: said disc having a coupling surface engaged by said drivingelement during said part of a revolution and a further coupling, surfacehaving an angular extent substantially less than that corresponding toone revolution of said disc and disposed to be engaged by said drivingelement when said clutch is disengaged to drive said control disc to alimited extent until said further coupling surface becomes disengagedfrom said driving element.

3. Automatic mechanism for phonograph rec,- crd playing apparatuscomprising a control disc, means for driving said disc, a clutchincluding a driven element coupled to said disc, a driving elementcoupled to said driving means, said disc having a coupling surface forengagement by said driven element, said disc having a further couplingsurface of smaller angular extent than said first-mentioned couplingsurface with which said driving element can engage, means for movingsaid driving element into engagement with said driven element to rotatesaid control disc through a substantial part of a revolution, and meansfor disengaging said driving element from said driven element at aposition when said further coupling surface can be engaged by saiddriving element thereby to drive said control disc for a limited angularextent until said further coupling surface is moved out of engagementwith said driving element. 7

4. Automatic mechanism for phonograph rec- 0rd playing apparatuscomprising a control disc, means for rotating said disc, a clutchincluding a driven element coupled to said disc and a driving elementcoupled to said driving means, a earn rotatable With said control disc,and a cam follower connected to said driving element to controlengagement and disengagement of driving and driven elements, saidcontrol disc having a surface to drive said control disc for asubstantial degree by said driven element and a further surface forengagement by said driving element to drive said control disc to alimited extent when said driving and driven elements are disengaged andsaid driven element is disengaged from said first-mentioned surface.

5. Automatic mechanism for phonograph reoord playing apparatuscomprising a control disc having gear teeth on a periphery thereof,means for rotating said disc, a clutch including a driven element in theform of a gear Wheel engaging said teeth and a driving element in theform of a gear Wheel coupled to said driving means, a cam rotatable withsaid control disc, a cam follower engaging said cam and connected tosaid 6 driving element, and further gear teeth on said control disc,said further gear teeth "seine posed to be engaged by driving elementwhen said driving and driven elements are disengaged to drive saidcontrol disc for a limited extent after said'driven element isdisengaged from said first-mentioned gear teeth.

ALEXAYDER JAPHES RAE.

References Cited in the file of this patent UNITED STATES PATENTS NameDate 1,195,793 Preuss July 6, 1915 1,532,116 Batchelder Apr. 7, 19251,942,158 Winchell Jan. 2, 1934. 2,059,595 Thomas Feb. 2, 1937 2,142,257Sal-ta Jan. 3, 1939 2,214,982 Schmidt Sept. 10, 1940 2,432A83 Miller eta1 Dec. 9, 1947 2,442,574 Storck June 1, 1948 2,532,266 Andres Nov. 28,1950

